javascript - amCharts 工具提示仅在 DateAxis 上显示，但在 ValueAxis 上不显示

Question

我正在使用 amCharts，并且正在制作包含多个系列的 XY 图表，工具提示仅在 X 轴类型为 DateAxis 时显示，但在 X 轴类型为 ValueAxis 时则不起作用>

var dateAxis = chart5.xAxes.push(new am4charts.DateAxis());
series.dataFields.dateX = "time";

带有工具提示的 amChart:

现在，当我将这两行更改为值轴时，它不起作用

var dateAxis = chart5.xAxes.push(new am4charts.ValueAxis());
    series.dataFields.valueX = "time";

不带工具提示的 amChart:

Answer 1

我遇到了同样的问题，并深入研究了 library code ，我意识到 ValueAxis 没有实现 getSeriesDataItem方法( DateAxis 和 CategoryAxis 执行)。所以，我的解决方案是实现该方法。基于其他轴实现，我得出的代码是:

am4charts.ValueAxis.prototype.getSeriesDataItem = function (series, position) {
    var key = this.axisFieldName + this.axisLetter;
    var value = this.positionToValue(position);
    return series.dataItems.getIndex(series.dataItems.findClosestIndex(value, function(x) {
        return x[key];
    }, "any"));
}

添加此原型(prototype)后，使用 ValueAxis 时工具提示可以正常工作:

/********** FIX: Add getSeriesDataItem method to ValueAxis ************/
am4charts.ValueAxis.prototype.getSeriesDataItem = function (series, position) {
    var key = this.axisFieldName + this.axisLetter;
    var value = this.positionToValue(position);
    return series.dataItems.getIndex(series.dataItems.findClosestIndex(value, function(x) {
        return x[key];
    }, "any"));
}
/**********************************************************************/
/* Create chart instance */
var chart = am4core.create("chartdiv", am4charts.XYChart);

/* Add data */
chart.data = [{
  "xValue": 1000,
  "yValue": 1587
}, {
  "xValue": 1100,
  "yValue": 1567
}, {
  "xValue": 1250,
  "yValue": 1617
}, {
  "xValue": 1400,
  "yValue": 1630
}, {
  "xValue": 1700,
  "yValue": 1660
}, {
  "xValue": 1754,
  "yValue": 1683
}, {
  "xValue": 2255,
  "yValue": 1691
}, {
  "xValue": 3004,
  "yValue": 1298
}];

/* Create axes */
var theXAxis = chart.xAxes.push(new am4charts.ValueAxis());

/* Create value axis */
var theYAxis = chart.yAxes.push(new am4charts.ValueAxis());

/* Create series */
var series1 = chart.series.push(new am4charts.LineSeries());
series1.dataFields.valueY = "yValue";
series1.dataFields.valueX = "xValue";
series1.name = "The X Axis";
series1.bullets.push(new am4charts.CircleBullet());
series1.tooltipText = "{valueY}";

/* Add legend */
chart.legend = new am4charts.Legend();

/* Create a cursor */
chart.cursor = new am4charts.XYCursor();

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
}

#chartdiv {
  width: 100%;
  height: 300px;
}

<script src="//www.amcharts.com/lib/4/core.js"></script>
<script src="//www.amcharts.com/lib/4/charts.js"></script>
<div id="chartdiv"></div>